Bristol Myers Squibb Announces China Approval of Camzyos (Mavacamten), the First-in-Class Cardiac Myosin Inhibitor, for Adults with Symptomatic Obstructive Hypertrophic Cardiomyopathy

China Finance Network News, April 30 — Bristol-Myers Squibb announced today that the world's first cardiac myosin inhibitor, Myfentol (generic name: Mavacamten capsules), has been granted priority review and approval by the National Medical Products Administration (NMPA) for the treatment of adult patients with obstructive hypertrophic cardiomyopathy (HCM) classified as New York Heart Association (NYHA) functional class II-III, to improve exercise capacity and symptoms.

This approval is based on the global EXPLORER-HCM and Chinese EXPLORER-CN Phase III clinical studies, which showed that in Chinese patients with obstructive hypertrophic cardiomyopathy (obstructive HCM), Mavacamten demonstrated significant improvement in Valsalva left ventricular outflow tract (LVOT) peak pressure gradient. Additionally, improvements were observed across all secondary endpoints, including LVOT obstruction, clinical symptoms, health status, cardiac biomarkers, and cardiac structure. In terms of safety, Mavacamten was well-tolerated in Chinese patients with obstructive HCM and exhibited a safety profile consistent with previous studies.

Data show that hypertrophic cardiomyopathy is mainly caused by pathogenic variants in genes encoding sarcomere-related proteins, or it may be a cardiomyopathy of unknown etiology, characterized by myocardial hypertrophy, with the left ventricular wall being most commonly affected. The prevalence rate in China, adjusted for age and gender, is approximately 80 per 100,000. Based on the presence or absence of left ventricular outflow tract (LVOT) obstruction, hypertrophic cardiomyopathy can be divided into two main types: obstructive and non-obstructive.

Patients typically experience symptoms such as exertional dyspnea, chest pain, palpitations, and syncope, and may even develop severe complications, leading to disease deterioration or death. Although the incidence of sudden cardiac death (SCD) is only 1%, it remains one of the leading causes of mortality in HCM patients, particularly prominent in younger patients.

Professor Zhang Shuyang, principal investigator of the EXPLORER-CN study and president of Peking Union Medical College Hospital, noted that patients with left ventricular outflow tract obstruction have a lower survival rate compared to those with non-obstructive HCM. Conventional medications can only alleviate symptoms and do not fundamentally address the series of clinical syndromes caused by myocardial hypertrophy. While surgical or interventional treatments may improve HCM symptoms, these invasive procedures are technically challenging and carry risks of complications, leading to very few patients opting for them. As such, they have not been widely adopted in clinical practice, underscoring the urgent need for innovative new drugs to transform the current treatment landscape.

"Mavacamten is an innovative therapeutic drug in the field of hypertrophic cardiomyopathy treatment, and its efficacy and safety have been confirmed in multiple international studies. The EXPLORER-CN study conducted on Chinese patients also demonstrated that Mavacamten can bring significant benefits to Chinese patients," said Professor Zhang Shuyang. She noted that the approval of Mavacamten in China has ushered in a new era for the treatment of obstructive HCM in China, with the potential to redefine the treatment prospects for such patients.

It is reported that the excessive formation of myosin and actin cross-bridges, as well as the dysregulation of myosin's super-relaxed state, are mechanistic features of HCM. As the world's first cardiac myosin inhibitor, Mavacamten targets the core pathophysiological mechanism of the disease. By reversibly binding to cardiac myosin, it reduces the number of myosin and actin cross-bridges, thereby alleviating excessive myocardial contraction and improving diastolic function.

Currently, Mavacamten has been included in the "2023 European Society of Cardiology (ESC) Guidelines for the Management of Cardiomyopathy," the "2023 Chinese Guidelines for the Diagnosis and Treatment of Adult Hypertrophic Cardiomyopathy," and the "2022 Chinese Hypertrophic Cardiomyopathy Guidelines" as one of the recommended therapies for patients with obstructive hypertrophic cardiomyopathy.

Bristol-Myers Squibb Vice President, General Manager of China and Asian Regional Markets, and President of China, Serena Chen, stated that China’s support for the approval of innovative drugs is continuously increasing. As the first innovative drug approved in the cardiovascular field since the implementation of Bristol-Myers Squibb's "China 2030 Strategy," Mavacamten has already been approved in Macao and Hong Kong and officially launched in Boao, Hainan's "Medical Special Zone" earlier this year. "This approval is expected to bring a new treatment option to more patients with obstructive hypertrophic cardiomyopathy and improve their quality of life. We are currently actively collaborating with regulatory authorities to accelerate the drug's accessibility in China, hoping to benefit patients as soon as possible and help them lead tranquil lives."